Field of the Invention
The present invention relates to a sheet feeding apparatus for feeding sheets, and an image forming apparatus for forming images on sheets.
Description of the Related Art
In image forming apparatuses such as printers and copying machines, sheet feeding apparatuses equipped with a sheet feeding cassette that can be inserted in a drawable manner to the apparatus body and capable of feeding sheets stored in the cassette are used. In this type of sheet feeding apparatus, there are cases where a damper mechanism is arranged on the sheet feeding cassette or the apparatus body to prevent inconveniences such as displacement of sheets, damage of components and collision noise that may be caused when inserting the sheet feeding cassette to the apparatus body. Japanese Patent Laid-Open Publication No 2015-214424 discloses a sheet feeding apparatus having a dashpot-type oil damper and a pivot member arranged on a sheet feeding cassette, in which the pivot member activates the oil damper when abutted against an apparatus body.
Meanwhile, some sheet feeding apparatuses are equipped with a supporting member referred to as a supporting plate or an intermediate plate that may be lifted with respect to the sheet feeding cassette while supporting sheets. In many cases, this type of supporting member is lifted by drive force from a motor arranged on the apparatus body, and if the sheet feeding cassette is drawn out of the apparatus body, the supporting member is uncoupled from the motor and is lowered by its own weight. If the supporting member is lowered in a state close to free fall, the supporting member collides against a bottom portion of the sheet feeding cassette and problems such as displacement of sheets and collision noise may occur. Japanese Patent Application Laid-Open Publication No. H08-127434 discloses a configuration having a sheet supporting plate suspended by a wire rope, wherein a winding shaft of the wire rope is connected to a rotation-type oil damper, by which lowering action of the sheet supporting plate is damped.
One may consider implementing, in a single sheet feeding apparatus, both a shock absorbing function exerted during insertion of the sheet feeding cassette to the apparatus body and a function to reduce lowering speed of the supporting member during draw-out of the sheet feeding cassette from the apparatus body. Thereby, it is expected that a sheet feeding apparatus having a high usability and capable of overcoming inconveniences such as displacement of sheets both during draw-out of the sheet feeding cassette from the apparatus body and insertion thereof into the apparatus body can be achieved. However, if the configurations disclosed in the above-described documents are combined, providing two oil dampers exerting each functions will be needed, which leads to increase of costs.